text: #!/usr/bin/env python
  
  import vtk
  
  
  # arrow.py adapted from the C++ vtk examples and translated to python.
  
  def main():
      colors = vtk.vtkNamedColors()
  
      arrowSource = vtk.vtkArrowSource()
      # arrowSource.SetShaftRadius(0.01)
      # arrowSource.SetTipLength(.9)
  
      # Create a mapper and actor
      mapper = vtk.vtkPolyDataMapper()
      mapper.SetInputConnection(arrowSource.GetOutputPort())
      actor = vtk.vtkActor()
      actor.SetMapper(mapper)
  
      # Visualize
      renderer = vtk.vtkRenderer()
      renderWindow = vtk.vtkRenderWindow()
      renderWindow.SetWindowName("Arrow")
      renderWindow.AddRenderer(renderer)
      renderWindowInteractor = vtk.vtkRenderWindowInteractor()
      renderWindowInteractor.SetRenderWindow(renderWindow)
  
      renderer.AddActor(actor)
      renderer.SetBackground(colors.GetColor3d("MidnightBlue"))
  
      renderWindow.Render()
      renderWindowInteractor.Start()
  
  
  if __name__ == "__main__":
      main()
  